The Role of Timing in Shaping Information Processing in Neural Systems

In many biological systems, information about the environment is detected by a
large array of sensory receptors; it reaches more central regions of the nervous system
as parallel streams of spike trains. How this ‡ow of information is processed and which
features are most salient to the organism is a central problem in neuroscience. A com-
prehensive and systematic approach to the analysis of the relationships between stimuli
and their neural representations is illustrated. This approach is complementary to the
hypothesis driven research paradigm, where the investigator states a hypothesis and
then performs experiments in order to validate or invalidate the stated hypothesis. This
alternative methodology enlarges the possible relationships between stimuli and their
representations beyond one speci…c hypothesis and aims to evaluate all possible rela-
tionships between neural stimuli and their neural representations. For a speci…c set of
data, both the set of stimuli and the set of neural response are characterized either by
membership in discrete categories or as a continuous space with a similarity measure.
In order to quantify these input-output relationships, existing methods of analysis are
adapted or new ones developed where necessary. In the speci…c data sets analyzed here,
timing emerges as a critical parameter for the description of neural stimuli and their
representations.